The team is using publicly available sky images dating back to the 1950s to try to detect and analyze objects that have disappeared over time.
The Disappearing and Emerging Sources in a Century of Observation (VASCO) project, led by an international team of researchers, is looking for objects that existed in the old military sky catalogs of the 1950s and will no longer be found in modern sky surveys. Among the physical indicators they are looking for are stars that have disappeared into the Milky Way.
“Finding a truly vanishing star - or a star that appears out of nowhere - would be a precious discovery and would undoubtedly open a new chapter in astrophysics beyond what we know,” says project leader Beatrice Villarroel, Stockholm University and Canarias Institute for Astrophysics. Spain
When a star dies, it either changes very slowly and becomes a white dwarf, or dies from a sudden explosion, that is, it becomes a supernova. A vanishing star can be an example of an "impossible phenomenon" that can be attributed either to new astrophysical phenomena or to extraterrestrial activity. Indeed, the only explanation for the disappearing star other than ETI (extraterrestrial intelligence) would be the extremely rare "failed supernova" event. A failed supernova is theoretically predicted to occur when a very massive star collapses into a black hole with no visible explosion. Other physical indicators of ETI activity that the authors are looking for are signs of red interstellar communication lasers and Dyson spheres. The Dyson Sphere is a hypothetical giant structure that surrounds a star to harness its energy.
“As a by-product, VASCO has the potential to detect rare, highly variable objects. They could shed light on the fast, hard-to-see phases of stellar evolution and the active galactic core,”says co-author Sebastien Comeron, University of Oulu, Finland.
The researchers carefully examined about 15% of the 150,000 candidate objects in the available data and found about 100 highly variable objects or events in the sky. Some of these objects in a very short time flared at least 8-9 magnitudes, or several thousand times brighter.
“We are very excited about tracking down the processes that we found,” says Beatrice Villarroel.
“But it's clear to us that none of these events showed any direct indication that they are ETIs. We believe they are natural, albeit somewhat extreme, astrophysical sources,”says Martin López Correduara, co-author of the paper at the Institute of Astrophysics de Canaria, Spain.
Researchers are considering the possibility of organizing a civil science project, which is assisted by artificial intelligence. To be able to test all 150,000 candidates that have been identified from the material, they must accelerate the process of identifying anomalies in images.
“We hope to get help from the community to view the images as part of a civic science project. We are looking for ways to do this right now, and we can talk about it later,”says Lars Mattsson of Stockholm University.